Recycling device for acyl chloride synthesis tail gas

Abstract

The utility model relates to the technical field of chemical tail gas treatment, in particular to an acyl chloride synthesis tail gas recycling device, which aims to solve the problems that the acyl chloride synthesis tail gas recycling device in the prior art is easy to block and affects safe and stable production, and specifically comprises an absorption liquid buffer tank, a tail gas absorption pipeline and a circulating heat exchange pipeline, wherein the bottom of the absorption liquid buffer tank is provided with a first liquid outlet and a second liquid outlet, the top of the absorption liquid buffer tank is provided with a first liquid inlet, a second liquid inlet and a tail gas exhaust port, and the tail gas exhaust port is communicated with a tail gas leading-out pipe; the tail gas absorption pipeline comprises a first circulating conveying pipe, a first circulating conveying pump and a Venturi ejector; according to the utility model, gas-liquid mixing is realized through the venturi ejector, the volume of equipment is small, the occupied area is small, the gas-liquid contact area is large, and the absorption efficiency is high; a small amount of fatty acid or acyl chloride entrained in tail gas does not affect device operation; when the device runs, the Venturi ejector can generate negative pressure, the pressure drop of a tail gas pipeline can be reduced, and multi-stage series connection use can be achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to chemical tail gas treatment technical field especially relates to a kind of recovery and utilization device of acyl chloride synthesis tail gas. BACKGROUND

[0002] Acylation chloride occupies an important position in the field of organic synthesis and drug synthesis. Currently, the common methods for preparing acylation chloride include thionyl chloride method, phosphorus trichloride method, phosphorus pentachloride method, phosgene method and triphosgene method. Among them, phosgene method has become the dominant technology for industrial production of acylation chloride because of its advantages of short reaction period, low cost and high yield in synthesizing fatty acid acylation chloride.

[0003] However, a large amount of hydrogen chloride-containing tail gas is generated during the synthesis of acylation chloride by phosgene method. To treat these tail gases, water is usually used as the absorption liquid to absorb hydrogen chloride in the tail gas to produce hydrochloric acid as a byproduct. Traditionally, this tail gas treatment relies on a falling film absorber. To ensure high hydrogen chloride absorption efficiency, the falling film absorber often needs to be designed larger, sometimes even requiring multiple stages in series, and the falling film absorber increases the pressure drop of the tail gas pipeline, which is not suitable for too many stages in series.

[0004] In addition, a small amount of acylation chloride and fatty acid may be entrained in the acylation chloride synthesis tail gas. These impurities will gradually accumulate and clog the tubes of the falling film absorber during use, resulting in a decrease in absorption efficiency and an increase in pressure drop, making it difficult to maintain a negative pressure state in the phosgenation tail gas pipeline, and thus causing safety hazards. To solve this problem, the falling film absorber needs to be stopped and completely replaced before the unblocking operation can be performed, which has a significant impact on production activities. SUMMARY

[0005] The technical problem to be solved by the utility model is to provide a recovery and utilization device for acylation chloride synthesis tail gas to solve the problem of easy clogging of traditional acylation chloride synthesis tail gas recovery and utilization devices, which affects safe and stable production.

[0006] To achieve the above-mentioned purpose, the utility model adopts the following technical solutions:

[0007] A recovery and utilization device for acylation chloride synthesis tail gas, characterized by:

[0008] The recovery and utilization device for acylation chloride synthesis tail gas comprises an absorption liquid buffer tank, a tail gas absorption pipeline and a circulating heat exchange pipeline, wherein the bottom of the absorption liquid buffer tank is provided with a first liquid discharge port and a second liquid discharge port, the top of the absorption liquid buffer tank is provided with a first liquid inlet port, a second liquid inlet port and a tail gas exhaust port, the tail gas exhaust port is communicated with a tail gas outlet pipe, and the tail gas outlet pipe is communicated with a tail gas absorption pipeline.

[0009] The tail gas absorption pipeline comprises a first circulating conveying pipe, a first circulating conveying pump and a Venturi ejector, wherein the first circulating conveying pipe is connected with the first liquid outlet and the first liquid inlet of the absorption liquid buffer tank, the first circulating conveying pump and the Venturi ejector are sequentially arranged on the first circulating conveying pipe along the liquid flow direction, and the front end of the Venturi ejector is arranged opposite to the first liquid inlet, and the side interface of the Venturi ejector is connected with a tail gas inlet pipe.

[0010] The circulating heat exchange pipeline comprises a second circulating conveying pipe, a second circulating conveying pump and an absorption liquid cooler, wherein the second circulating conveying pipe is connected with the second liquid outlet and the second liquid inlet of the absorption liquid buffer tank, the second circulating conveying pump and the absorption liquid cooler are sequentially arranged on the second circulating conveying pipe along the liquid flow direction.

[0011] The absorption liquid supplement pipe and the hydrochloric acid discharge pipe are further arranged to be connected with the inside of the absorption liquid buffer tank.

[0012] The technical problem of the present application can be further solved by the following steps, one end of the absorption liquid supplement pipe is connected with the first circulating conveying pipe between the first liquid outlet and the first circulating conveying pump, the absorption liquid supplement pipe is connected with the inside of the absorption liquid buffer tank through the first circulating conveying pipe, and a liquid inlet valve is arranged on the absorption liquid supplement pipe.

[0013] The technical problem of the present application can be further solved by the following steps, the absorption liquid buffer tank is connected with a liquid level meter, and the liquid inlet valve and the liquid level meter are electrically connected.

[0014] The technical problem of the present application can be further solved by the following steps, one end of the hydrochloric acid discharge pipe is connected with the second circulating conveying pipe between the second circulating conveying pump and the absorption liquid cooler, the hydrochloric acid discharge pipe is connected with the inside of the absorption liquid buffer tank through the second circulating conveying pipe, and a liquid outlet valve is arranged on the hydrochloric acid discharge pipe.

[0015] The technical problem of the present application can be further solved by the following steps, a circulating detection branch is connected with the second circulating conveying pipe, one end of the circulating detection branch is arranged between the hydrochloric acid discharge pipe and the second circulating conveying pump, the other end of the circulating detection branch is arranged between the second circulating conveying pump and the second liquid outlet, a hydrochloric acid concentration detection table is arranged on the circulating detection branch, and the liquid outlet valve and the hydrochloric acid concentration detection table are electrically connected.

[0016] The technical problem of the present application can be further solved by the following steps, the absorption liquid cooler is a heat exchanger connected with a circulating water system, one end of the heat exchanger is provided with a circulating water inlet, and the other end of the heat exchanger is provided with a circulating water outlet.

[0017] The technical problems to be solved by the utility model can be further realized through the following steps, the liquid inlet flowmeter is installed on the absorption liquid supplement pipe, and the liquid outlet flowmeter is installed on the hydrochloric acid discharge pipe.

[0018] Compared with the prior art, the utility model has the advantages that: the Venturi ejector is used to realize gas-liquid mixing, the device has small volume and occupies small area, the gas-liquid contact area is large, the absorption efficiency is high, and a small amount of fatty acid or acyl chloride entrained in tail gas does not affect the operation of the device; the Venturi ejector can generate negative pressure during operation of the device, can reduce the pressure drop of the tail gas pipeline, and can be used in multiple stages in series; the first liquid outlet is arranged between the absorption liquid supplement pipe and the first circulating delivery pump, fresh absorption liquid can quickly reach the Venturi ejector to absorb tail gas after entering the device, the absorption efficiency is increased, and the concentration of hydrochloric acid in the tank is not diluted; the liquid inlet valve and the liquid outlet valve are both automatically controlled, can realize automatic liquid supplement and acid discharge, can be operated continuously in full automation, the by-product hydrochloric acid concentration is stable, and the problem of decreased absorption saturation efficiency during the acid discharge process in the traditional method does not occur. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a structural schematic view of the utility model;

[0020] In the figure: 1-absorption liquid buffer tank;101-first liquid outlet;102-second liquid outlet;103-first liquid inlet;104-second liquid inlet;105-tail gas exhaust port;2-tail gas leading-out pipe;3-first circulating delivery pipe;4-first circulating delivery pump;5-Venturi ejector;501-front end injection port;6-second circulating delivery pipe;7-second circulating delivery pump;8-absorption liquid cooler;9-absorption liquid supplement pipe;10-hydrochloric acid discharge pipe;11-liquid inlet valve;12-liquid level meter;13-liquid outlet valve;14-circulating detection branch;15-hydrochloric acid concentration detection table;16-liquid inlet flowmeter;17-liquid outlet flowmeter;18-thermometer;19-pressure gauge;20-tail gas leading-in pipe. DETAILED DESCRIPTION

[0021] The specific technical scheme of the utility model is further described below, so that those skilled in the art can further understand the utility model, and it does not limit the rights thereof.

[0022] In the description of the utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the utility model.

[0023] Please refer to Figure 1The utility model relates to an acyl chloride synthesis tail gas recycling device for recycling and utilizing hydrogen chloride in acyl chloride synthesis tail gas to prepare hydrochloric acid, which comprises an absorption liquid buffer tank 1, a tail gas absorption pipeline and a circulating heat exchange pipeline, wherein the bottom of the absorption liquid buffer tank 1 is provided with a first liquid discharge port 101 and a second liquid discharge port 102, the top of the absorption liquid buffer tank 1 is provided with a first liquid inlet port 103, a second liquid inlet port 104 and a tail gas exhaust port 105, the tail gas exhaust port 105 is communicated with a tail gas leading-out pipe 2,

[0024] The tail gas absorption pipeline comprises a first circulating conveying pipe 3, a first circulating conveying pump 4 and a venturi ejector 5, wherein the first circulating conveying pipe 3 communicates the first liquid discharge port 101 and the first liquid inlet port 103 of the absorption liquid buffer tank 1, the first circulating conveying pump 4 and the venturi ejector 5 are sequentially installed on the first circulating conveying pipe 3 along the liquid flow direction, the venturi ejector 5 has a rear end inlet, a side interface and a front end injection port, the front end injection port 501 of the venturi ejector 5 is arranged opposite to the first liquid inlet port 103, and the side interface of the venturi ejector 5 is communicated with a tail gas leading-in pipe 20; the first circulating conveying pump 4 punches the absorption liquid to the venturi ejector 5, and the hydrogen chloride in the tail gas is efficiently mixed and contacted at the venturi ejector 5 to be fully absorbed, thereby obtaining by-product hydrochloric acid; the structure of the venturi ejector 5 is well known to those skilled in the art, and will not be described here.

[0025] The circulating heat exchange pipeline comprises a second circulating conveying pipe 6, a second circulating conveying pump 7 and an absorption liquid cooler 8, wherein the second circulating conveying pipe 6 communicates the second liquid discharge port 102 and the second liquid inlet port 104 of the absorption liquid buffer tank 1, and the second circulating conveying pump 7 and the absorption liquid cooler 8 are sequentially installed on the second circulating conveying pipe 6 along the liquid flow direction; the absorption liquid cooler 8 can effectively reduce the temperature of the absorption liquid hydrochloric acid, increase the solubility of hydrogen chloride and increase the tail gas absorption efficiency.

[0026] It also comprises an absorption liquid supplement pipe 9 and a hydrochloric acid discharge pipe 10 which are communicated with the inside of the absorption liquid buffer tank 1.

[0027] The absorption liquid supplement pipe 9 is communicated with the inside of the absorption liquid buffer tank 1 in the following manner: one end of the absorption liquid supplement pipe 9 is connected to the first circulating conveying pipe 3 between the first liquid discharge port 101 and the first circulating conveying pump 4, the absorption liquid supplement pipe 9 is communicated with the inside of the absorption liquid buffer tank 1 through the first circulating conveying pipe 3, and a liquid inlet valve 11 is installed on the absorption liquid supplement pipe 9.

[0028] The liquid inlet valve 11 can be manually opened and closed, or automatically opened and closed in the following manner: the liquid level gauge 12 is connected to the absorption liquid buffer tank 1, and the liquid inlet valve 11 is electrically connected to the liquid level gauge 12; when the liquid level gauge 12 detects that the liquid level in the absorption liquid buffer tank 1 is lower than the set level, a control signal is sent to the PLC or DCS, and the PLC or DCS controls the liquid inlet valve 11 to open according to the preset program, so that fresh absorption liquid immediately enters the first circulating conveying pipe 3 through the absorption liquid supplement pipe 9 and quickly reaches the venturi injector 5 to absorb tail gas, thereby increasing the absorption efficiency and not diluting the concentration of hydrochloric acid in the tank.

[0029] The hydrochloric acid discharge pipe 10 is connected to the inside of the absorption liquid buffer tank 1 in the following manner: one end of the hydrochloric acid discharge pipe 10 is connected to the second circulating conveying pipe 6 between the second circulating conveying pump 7 and the absorption liquid cooler 8, the hydrochloric acid discharge pipe 10 is connected to the inside of the absorption liquid buffer tank 1 through the second circulating conveying pipe 6, and a liquid discharge valve 13 is installed on the hydrochloric acid discharge pipe 10.

[0030] The liquid discharge valve 13 can be manually opened and closed, or automatically opened and closed in the following manner: a circulating detection branch 14 is connected to the second circulating conveying pipe 6, one end of the circulating detection branch 14 is arranged between the hydrochloric acid discharge pipe 10 and the second circulating conveying pump 7, the other end of the circulating detection branch 14 is arranged between the second circulating conveying pump 7 and the second liquid discharge port 102, a hydrochloric acid concentration detection table 15 is installed on the circulating detection branch 14, and the liquid discharge valve 13 is electrically connected to the hydrochloric acid concentration detection table 15; when the hydrochloric acid concentration detection table 15 detects that the concentration of hydrochloric acid in the second circulating conveying pipe 6 reaches a set value, a control signal is sent to the PLC or DCS, and the PLC or DCS controls the liquid discharge valve 13 to open to discharge the hydrochloric acid according to the preset program; the liquid discharge valve 13 can gradually increase or decrease the opening degree to adjust the discharge flow of the hydrochloric acid according to the difference between the detection value and the set value of the hydrochloric acid concentration detection table 15, thereby realizing automatic control.

[0031] The absorption liquid cooler 8 is specifically a heat exchanger connected to a circulating water system, one end of the heat exchanger is provided with a circulating water inlet, and the other end of the heat exchanger is provided with a circulating water outlet. The circulating water forms a closed loop in the heat exchanger and continuously takes away the heat of the absorption liquid, thereby ensuring that the temperature of the absorption liquid is always maintained at a low level that is conducive to the absorption of hydrogen chloride.

[0032] A liquid inlet flowmeter 16 is installed on the absorption liquid supplement pipe 9, and a liquid discharge flowmeter 17 is installed on the hydrochloric acid discharge pipe 10. The liquid inlet flowmeter 16 and the liquid discharge flowmeter 17 are connected to the PLC or DCS, and real-time flow data is fed back to facilitate the monitoring and adjustment of the operating state of the system by the operator.

[0033] The absorption liquid buffer tank is also provided with a thermometer 18 and a pressure gauge 19, and the absorption liquid in the embodiment is water.

[0034] Working principle: the acyl chloride synthesis tail gas recycling device aims at recycling hydrogen chloride in tail gas and preparing hydrochloric acid, in use, first, the absorption liquid is injected into the absorption liquid buffer tank 1 through the absorption liquid supplement pipe 9 until the liquid level reaches the set value, then the circulating water inlet and outlet valves on the heat exchanger are opened, so that the low-temperature circulating water forms a closed circuit in the heat exchanger to provide continuous cooling effect for the absorption liquid, then the first circulating pump 4 and the second circulating pump 7 are started, the first circulating pump 4 draws the absorption liquid from the first liquid outlet 101 of the absorption liquid buffer tank 1, and sends it into the venturi ejector 5 after pressurization, at the same time, the acyl chloride synthesis tail gas is introduced into the side interface of the venturi ejector 5 through the tail gas introduction pipe 20, and is mixed with the absorption liquid under the action of the venturi effect, and the hydrogen chloride in the tail gas is converted into hydrochloric acid solution, as the reaction proceeds, the concentration of the hydrochloric acid solution gradually increases, and when the concentration of the hydrochloric acid reaches the required concentration, the liquid valve 13 is automatically opened to discharge the acid, during the whole process, the liquid inlet valve 11 is automatically opened and closed according to the reading of the liquid level meter 12 to maintain the liquid level in the absorption liquid buffer tank 1.

[0035] Obviously, the described embodiments are part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

Claims

1. An acyl chloride synthesis tail gas recycling device, characterized in that: it comprises an absorption liquid buffer tank, a tail gas absorption pipeline and a circulating heat exchange pipeline, wherein the bottom of the absorption liquid buffer tank is provided with a first liquid discharge port and a second liquid discharge port, the top of the absorption liquid buffer tank is provided with a first liquid inlet port, a second liquid inlet port and a tail gas exhaust port, the tail gas exhaust port is communicated with a tail gas leading-out pipe; the tail gas absorption pipeline comprises a first circulating conveying pipe, a first circulating conveying pump and a Venturi ejector, wherein the first circulating conveying pipe is communicated with the first liquid discharge port and the first liquid inlet port of the absorption liquid buffer tank, the first circulating conveying pump and the Venturi ejector are sequentially installed on the first circulating conveying pipe along the liquid flow direction, and the front end of the Venturi ejector is provided with a jet port facing the first liquid inlet port, and the side interface of the Venturi ejector is communicated with a tail gas leading-in pipe; the circulating heat exchange pipeline comprises a second circulating conveying pipe, a second circulating conveying pump and an absorption liquid cooler, wherein the second circulating conveying pipe is communicated with the second liquid discharge port and the second liquid inlet port of the absorption liquid buffer tank, and the second circulating conveying pump and the absorption liquid cooler are sequentially installed on the second circulating conveying pipe along the liquid flow direction; it further comprises an absorption liquid supplement pipe and a hydrochloric acid discharge pipe which are communicated with the inside of the absorption liquid buffer tank. One end of the absorption liquid supplement pipe is connected to the first circulating conveying pipe between the first liquid discharge port and the first circulating conveying pump, the absorption liquid supplement pipe is communicated with the inside of the absorption liquid buffer tank through the first circulating conveying pipe, and a liquid inlet valve is installed on the absorption liquid supplement pipe. The absorption liquid buffer tank is connected with a liquid level meter, and the liquid inlet valve is electrically connected with the liquid level meter. One end of the hydrochloric acid discharge pipe is connected to the second circulating conveying pipe between the second circulating conveying pump and the absorption liquid cooler, the hydrochloric acid discharge pipe is communicated with the inside of the absorption liquid buffer tank through the second circulating conveying pipe, and a liquid discharge valve is installed on the hydrochloric acid discharge pipe. A circulating detection branch is connected to the second circulating conveying pipe, one end of the circulating detection branch is arranged between the hydrochloric acid discharge pipe and the second circulating conveying pump, the other end of the circulating detection branch is arranged between the second circulating conveying pump and the second liquid discharge port, a hydrochloric acid concentration detection table is installed on the circulating detection branch, and the liquid discharge valve is electrically connected with the hydrochloric acid concentration detection table.

2. The device for recycling acyl chloride synthesis tail gas according to claim 1, characterized in that: The absorption liquid cooler is specifically a heat exchanger connected with a circulating water system, one end of the heat exchanger is provided with a circulating water inlet, and the other end of the heat exchanger is provided with a circulating water outlet.

3. The device for recycling acyl chloride synthesis tail gas according to claim 2, characterized in that: A liquid inlet flowmeter is installed on the absorption liquid supplement pipe, and a liquid discharge flowmeter is installed on the hydrochloric acid discharge pipe.

4. The acyl chloride synthesis off-gas recycling apparatus according to claim 1, characterized by: ​ 5. The acyl chloride synthesis off-gas recycling apparatus according to claim 4, characterized by: ​ 6. The acyl chloride synthesis off-gas recycling apparatus according to claim 1, characterized by: ​ 7. The acyl chloride synthesis off-gas recycling apparatus according to claim 1, characterized by: ​

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